166 ON THE NATURE AND PRINCIPLES OF 



must lend its aid, by tracing (as far as its limited 

 power will permit) the degree of connection existing 

 between the appearance of each minute element of 

 morbid development and the composition of the 

 plasma and blood from Avhich it is formed. And 

 even where chemistry and the microscope fail to 

 elucidate the point selected for examination, ex- 

 periments on the living body having the conditions 

 of each so judiciously varied from those preceding 

 it, and at the same time so skilfully combined, as 

 invariably to lead to some definite conclusion will, 

 if I mistake not, be found to constitute a synthetical 

 mode of investigation, by the aid of which results 

 of striking novelty and vast importance may, in 

 many instances, be rapidly attained. In short, the 

 chemist, the microscopical observer, and the experi- 

 mental pathologist, must co-operate in studying the 

 nature of morbid actions ; and it is only by the 

 concentration of their respective energies upon the 

 same point that we can ever hope to acquire any 

 considerable number of sound pathological generali- 

 sations, or useful hygienic and therapeutical precepts. 

 But, to return from this slight digression to the 

 consideration of the phenomenon which suggested 

 these remarks ; it docs not, I think, involve any 

 great deviation from the rules of correct reasoning 

 to suppose that the power which, in the liquor 

 sanguinis present in the vessels of an inflamed part 

 evolves a mass of coherent globules, is, in its essen- 

 tial nature, not very far removed from that which 

 induces the natural coagulation of the fibrinous 

 portion of the blood. It can be shown that a 



